Safety device for an internal combustion engine

ABSTRACT

A safety device for an internal combustion engine of the type having a gas control valve on the carburetor connected by a suitable linkage to a manually operable throttle control member. A pair of electrical contacts are respectively fixed to the linkage and to the throttle control member. One of the pair of contacts is connected to electrical ground and the other of the pair of contacts is connected to the ignition of the internal combustion engine. A suitable spring normally returns the valve to a closed position when the throttle control member is released. If the linkage should stick with the flow control valve in the open position, when the throttle control member is released, the contacts close to ground the ignition and stop the engine.

United States Patent Albertson June 27, 1972 [54] SAFETY DEVICE FOR AN INTERNAL COMBUSTION ENGINE Robert V. Albertson, 2100 Shady Wood Road, Minneapolis, Minn.

221 Filed: Sept.ll, 1970 21 Appl.No.: 71,600

[72] inventor:

[52] US. Cl. ..l23/l98 DB, 123/98, 123/108 [51] Int. Cl ..F02b 77/08 [58] Field of Search ..123/98, 108,118, 198 R, 198 D,

123/198 DB, 198 DC; 251/294, 295, 305; ZOO/61.86, 61.87, 61.88, 61.89, 61.90

3,480,840 11/1969 Stephani .200/6190 Primary Examiner-Martin P. Schwadron Assistant Examiner-Clemens Schlmlkowski Attorney-Alfred E. Hall [57] ABSTRACT A safety device for an internal combustion engine of the type having a gas control valve on the carburetor connected by a suitable linkage to a manually operable throttle control member. A pair of electrical contacts are respectively fixed to the linkage and to the throttle control member. One of the pair of contacts is connected to electrical ground and the other of the pair of contacts is connected to the ignition of the internal combustion engine. A suitable spring normally returns the valve to a closed position when the throttle control member is released. If the linkage should stick with the flow control valve in the open position, when the throttle control member is released, the contacts close to ground the ignition and stop the engine.

6 Claims, 2 Drawing Figures PATENTEIJJUNZT 1972 3.672.344

INVENTOR ROBERT V. ALBER SON BY @541 f ATTORNEY SAFETY DEVICE FOR AN INTERNAL COMBUSTION ENG BACKGROUND OF THE INVENTION The present invention relates to a safety device for an internal combustion engine. Many automotivetype vehicles such as snowmobiles, all terrain vehicles, minibikes,etc. have a throttle system including a gas flow control valve on the carburetor, manually operable throttle control member which is usually mounted on a steering handle bar and a steel cable which connects the throttle control member to the gas flow control valve. The flexible cable is conventionally encased totally or, at least partially, in a flexible steel shroud which serves to guide the cable. It is well known that these cables must be properly lubricated regularly to prevent undue wear and sticking. 'However, wear does occur and, eventually, because of either lack of lubrication or otherwise, the cable becomes frayed and may stick or bind. Should the cable become stuck in the open position, i.e. in the position in which the gas control valve is open, serious injuries to the operator could result.

The present invention overcomes the disadvantages of the prior art throttle control systems by providing a device for grounding the vehicles electrical ignition circuit whenever the throttle cable sticks in an open position, thus preventing the engine from running and, therefore, preventing needless injury to individuals and damage to valuable property.

In accordance with the teaching of the present invention, this is accomplished by providing a pair of cooperating electrical contacts, one of the pair being fixed to the cable and'the other pair being fixed to the throttle control member. The arrangement is such that the contacts only become closed to ground the ignition circuit when the throttle control cable remains in a position where the gas control valve is opened at the time that the throttle control member is moved to its normally closed position. v

Accordingly, it is an object of the present invention to provide a simple and reliable safety switch for an internal combustion engine to ground the ignition in the event the gas control sticks in an open position when an attempt is made to throttle down to an idle position. I

Other objects of the invention will become apparent from the following description taken in connection with the accompanying drawings in which: I

FIG. I is a somewhat schematic representation of the safety device, and

FIG. 2 illustrates the manner in which the invention can be adapted to vehicles or other devices utilizing internal combustion engines with a twist grip typethrottle control member.

Referring now to FIG. I, there is shown an internalcombustion engine indicated generally by numeral 10. The internal combustion engine has a flywheel operated magneto (not shown) which functions to provide high voltage to a spark plug 12 by way of a cable 14. Engine is also provided with a carburetor 16 having a gas flow control valve (not shown) operated by an elbow linkage 18. The elbow linkage 18 is normally urged to a position in which the flow control valve is closed by a spring 20.

Because the motor and associated linkage 18 are often in an inconvenient or inaccessible location, means are provided for operating the motor from a remote location. In the prior art, it is quite conventional to utilize a coaxial cable 22 having an outer sheath 24 and a central wire 26 passing therethrough. The outer sheath 24 is secured to the motor or framework in which the motor is utilized by means of cable clamps 28. The wire 26 is secured at one end to the elbow linkage I8 and at the other end to a suitable throttle control member such that when the throttle control member is operated, the wire 26 moves withinside the sheath 28 to operate the elbow linkage 18.

In FIG. 1, the throttle control member is illustrated as comprising a lever 30 pivotally mounted at pivot point 32 so as to be movable in a direction illustrated by the arrow 34. The

lever 30 is normally urged by means of a spring 36 to a position in which the gas flow control valve in carburetor 16 is in a closed or idling position.

Affixed to the wire 26 in close proximity to the lever 30 is a first of a pair of electrical contacts 38. Contact 38 is connected to ground 40 by means of a conductor. lf said lever is constructed of electrically conductive material, said contact 44 is electrically insulated from said lever. Mounted on the lever 30 is a second of a pair of contacts 44. An aperture 46 passes through contact 44 and lever 30. The wire 26 in cable 22 passes through aperture 46 and is provided at its extremity with a protrusion or knob 48 which is larger in size than the aperture so that as the lever 30 is moved to the right, the wire 26 is also pulled to the right and the elbow linkage 18 is moved in a direction to open the gas flow control valve in carburetor 16. So long as the cable is properly lubricated and in good working order, the spring 20 has sufficient force to move the flow control valve to the closed position and move the wire 26 to the left when the lever 30 is moved to the left. However, should the cable become frayed or for any other reason bind within the sheath 24 upon being moved to the right to open the gas flow control valve, when the lever 30 is released and moved to the left, the contact 44 on lever 30 will come in contact with the contact 38 affixed to the wire 26. This will complete the electrical circuit from ground 40 through conductor 42 and conductor 48 to ground the spark plug 12 and shut off the motor.

Referring to FIG. 2, there is illustrated the manner in which the present invention can be used with a twist grip type throttle control member. In its simplest form the twist grip control consists of a cylindrical member 50 having a series of ridges and valleys 52 adapted to conform to an operators hand. The grip is adapted to be rotated about a central handlebar 54 as indicated by the arrow 56. Protruding from the grip member 50 is a lug 58 having an aperture 60 passing therethrough. The outer sheath 24 of the flexible cable is secured by a cable clamp 28 to the handlebar 54. The wire 26 of the flexible cable passes through the aperture 60 in lug 58 and is terminated with a protrusion or enlargement 62. Fastened to one side of lug 58 is an electrically conductive contact member 64 and in a manner similar to that shown in FIG. 1 a second of a pair of contacts 66 is affixed to the wire 26 and movable therewith.

When the twist grip is rotated in the clockwise direction, the wire 26 will be withdrawn from the sheath 24 and the contacts 64 and 66 will remain in their spaced apart relationship. When the linkage assembly is in proper operating condition, the spring bias normally returning the gas flow control valve to its closed position will be strong enough to also move the wire 26 and contact 66 to the left. However, should the cable become frayed or should the cable be improperly lubricated, when the twist grip 50 is moved in the clockwise direction to open the gas flow control valve, it may stick in that position. Now, when the twist grip is rotated in the counterclockwise direction to idle down the motor, the contact 64 will move against contact 66 to complete an electrical circuit from ground to the spark plug of the internal combustion engine. As a result, the engine will be shut down.

The foregoing description and accompanying drawings clearly disclose preferred embodiments of the invention, but it will be understood that this disclosure is merely illustrative and that changes may be made within the scope of the following claims.

What is claimed is:

l. A mechanism for stopping an internal combustion engine in the event the throttle control linkage sticks, said engine having a gas flow control valve normally biased to a closed position and comprising:

a. a throttle control member movable between first and second positions;

b. resilient means urging said throttle control member toward said first position;

c. linkage means coupled at one end to said gas flow control valve;

d. means coupling the other end of said linkage to said throttle control member for enabling corresponding movement of said valve with movement of said member and simultaneously allowing relative movement between said member and said linkage if said linkage sticks; a pair of normally spaced apart electrical contacts, one of said pair being affixed to said member and the other of said pair being connected to said linkage; and means connecting one of said pair of contacts to electrical ground and the other of said pair to the ignition of said internal combustion engine whereby said contacts close and ground said ignition if said linkage sticks and said throttle control member is urged toward said first position. Apparatus as in claim 1 wherein said linkage includes:

a coaxial cable having an outer sheath fixedly secured to said engine; and b. a center wire slidably movable within said sheath, one

end of said wire being coupled to said gas flow control valve and the other end cooperating with said throttle member comprises:

a. a cylindrically shaped twist grip mounted for rotation about a rod member. 5. Apparatus as in claim 4 wherein said means coupling said 5 linkage to said throttle control member comprises:

a. means on said twist grip with an aperture therein through which said linkage wire is adapted to pass, said aperture being of a diameter greater than the diameter of said wire passing there through, and

b. an enlargement coupled to the end of said wire passing through said aperture to prevent said wire from withdrawing from said aperture and to provide positive coupling between said member and said wire.

6. A method of stopping an internal combustion engine in 15 the event the throttle control linkage sticks, said engine having a throttle control member biased towards a first position, a gas flow control valve, and a linkage coupling said member and said valve to cause corresponding movement of said valve with movement of said member, said method comprising the steps of:

control member. 3. Apparatus as in claim 2 wherein said means coupling said linkage to said throttle control member comprises:

a. an aperture in said member for receiving said linkage wire, said aperture being of a diameter greater than the diameter of said wire passing through; and

b. an enlargement coupled to the end of said wire passing through said aperture to prevent said wire from withdrawing from said aperture and to provide positive coupling between said member and said wire.

4. Apparatus as in claim 2 wherein said throttle control a. affixing a pair of electrical contacts in a spaced apart relationship to said linkage and said member;

b. coupling said linkage to said member to allow relative movement between said linkage and said member if said linkage sticks; and

c. connecting one of said pair of contacts to electrical ground and the other of said pair to ignition of said internal combustion engine whereby the bias on said member towards said first position closes said contacts and grounds said ignition if said linkage sticks. 

1. A mechanism for stopping an internal combustion engine in the event the throttle control linkage sticks, said engine having a gas flow control valve normally biased to a closed position and comprising: a. a throttle control member movable between first and second positions; b. resilient means urging said throttle control member toward said first position; c. linkage means coupled at one end to said gas flow control valve; d. means coupling the other end of said linkage to said throttle control member for enabling corresponding movement of said valve with movement of said member and simultaneously allowing relative movement between said member and said linkage if said linkage sticks; e. a pair of normally spaced apart electrical contacts, one of said pair being affixed to said member and the other of said pair being connected to said linkage; and f. means connecting one of said pair of contacts to electrical ground and the other of said pair to the ignition of said internal combustion engine whereby said contacts close and ground said ignition if said linkage sticks and said throttle control member is urged toward said first position.
 2. Apparatus as in claim 1 wherein said linkage includes: a. a coaxial cable having an outer sheath fixedly secured to said engine; and b. a center wire slidably movable within said sheath, one end of said wire being coupled to said gas flow control valve and the other end cooperating with said throttle control member.
 3. Apparatus as in claim 2 wherein said means coupling said linkage to said throttle control member comprises: a. an aperture in said member for receiving said linkage wire, said aperture being of a diameter greater than the diameter of said wire passing through; and b. an enlargement coupled to the end of said wire passing through said aperture to prevent said wire from withdrawing from said aperture and to provide positive coupling between said member and said wire.
 4. Apparatus as in claim 2 wherein said throttle control member comprises: a. a cylindrically shaped twist grip mounted for rotation about a rod member.
 5. Apparatus as in claim 4 wherein said means coupling said linkage to said throttle control member comprises: a. means on said twist grip with an aperture therein through which said linkage wire is adapted to pass, said aperture being of a diameter greater than the diameter of said wire passing there through, and b. an enlargement coupled to the end of said wire passing through said aperture to prevent said wire from withdrawing from said aperture and to provide positive coupling between said member and said wire.
 6. A method of stopping an internal combustion engine in the event the throttle control linkage sticks, said engine having a throttle control member biased towards a first position, a gas flow control valve, and a linkage coupling said member and said valve to cause corresponding movement of said valvE with movement of said member, said method comprising the steps of: a. affixing a pair of electrical contacts in a spaced apart relationship to said linkage and said member; b. coupling said linkage to said member to allow relative movement between said linkage and said member if said linkage sticks; and c. connecting one of said pair of contacts to electrical ground and the other of said pair to ignition of said internal combustion engine whereby the bias on said member towards said first position closes said contacts and grounds said ignition if said linkage sticks. 